1. Field of the Invention
This invention relates to paper transport devices and more particularly to paper transport rollers of the type having paper perforation engaging pins.
2. Prior Art
This invention is directed to that class of devices which are used for the transportation of paper having perforations along both sides. Such devices are normally used in printing devices, and in particular teleprinters, to draw the paper around a platen in a controlled paper movement manner. The platen is usually equipped with pin wheel rims at both ends thereof.
In this connection, it is known in teleprinters and other printing devices which employ perforated paper, to provide the platen with pin wheel rims which are firmly connected adjacent the ends of the platen. For various constructional reasons, the provision of pin wheel rims having fixed pins positioned over the entire circumference of the platen frequently presents difficulties. It has therefore been proposed to provide a radial movement to the pins by means of a cam control mechanism. In this type of construction those areas of the mechanism in which fixed pins would constitute an obstruction may be freed for structural members.
Because of the complexity of pin movement devices, such as the above mentioned cam control constructions, it is a desire of this invention to provide a paper transport device which facilitates movement of the paper in a controlled manner by means of pins which project, or which operatively project, only over a portion of the circumference of the platen. However, it is desired to construct the device in such a manner as to avoid the heretofore used cam controlled radial movement guided pins and to thereby achieve a technologically simplier device.